Rubber composition with organic salt curing agent

Abstract

A rubber composition comprising a metal salt of a carboxylic acid used as a curing agent, a highly unsaturated dieene rubber, a filler and a sulfur vulcanization system of between 0.5 phr and 8 phr of sulfur and at least one vulcanization accelerator. Particular embodiments may further include between 1 phr and 6 phr of a metal salt of a carboxylic acid that increases a tear index of the cured elastomer composition by at least 50 percent as compared to a similar cured elastomer composition, such similar cured elastomer composition being different in composition only in that it (1) lacks the metal salt of a carboxylic acid and (2) has an increased amount of the sulfur vulcanization system at about the same sulfur to accelerator ratio to maintain a 10% modulus of elongation at 23 0C to within 15% of the modulus of the cured rubber composition.

1 . A cured rubber composition that is based upon a cross-linkable rubber composition, the cross-linkable rubber composition comprising, per 100 parts by weight of rubber:
 a highly unsaturated diene rubber;   between 20 phr and 150 phr of a filler;   a sulfur vulcanization system of between 0.5 phr and 8 phr of sulfur and at least one vulcanization accelerator, the sulfur vulcanization system having a sulfur to accelerator ratio; and   between 1 phr and 6 phr of a metal salt of a carboxylic acid that increases a tear index of the cured elastomer composition by at least 50 percent as compared to a similar cured elastomer composition, wherein the similar cured elastomer composition is different in composition only in that the similar cured elastomer composition (1) lacks the metal salt of a carboxylic acid and (2) has an increased amount of the sulfur vulcanization system at about the same sulfur to accelerator ratio, the amount increased to maintain a 10% modulus of elongation at 23° C. to within 15% of the modulus of the cured rubber composition.   
     
     
         2 . The cured rubber composition of  claim 1 , wherein the metal salt is selected from zinc dimethacrylate, zinc diacrylate or combinations thereof. 
     
     
         3 . The cured rubber composition of  claim 1 , wherein the metal salt is selected from magnesium dimethacrylate, magnesium diacrylate or combinations thereof. 
     
     
         4 . The cured rubber composition of  claim 1 , wherein the metal salt of the carboxylic acid is selected from a salt of a metal that is selected from sodium, potassium, iron, magnesium, calcium, zinc, barium, aluminum, tin, zirconium, lithium, cadmium or cobalt. 
     
     
         5 . The cured rubber composition of  claim 1 , wherein the metal salt of a carboxylic acid is in an amount of between 1 phr and 4 phr. 
     
     
         6 . The cured rubber composition of  claim 1 , further comprising:
 between 1 phr and 40 phr of a plasticizing material.   
     
     
         7 . The cured rubber composition of  claim 6 , wherein the similar cured elastomer composition is further different in composition by having an increased amount of the plasticizing material equal to the quantity of metal salt added to the cured rubber composition. 
     
     
         8 . The cured rubber composition of  claim 7 , wherein the 10% Modulus of elongation at 23° C. is maintained to within 10% of the modulus of the cured rubber composition. 
     
     
         9 . The cured rubber composition of  claim 1 , wherein the highly unsaturated diene rubber is natural rubber. 
     
     
         10 . The cured rubber composition of  claim 1 , wherein the highly unsaturated diene rubber is a synthetic rubber selected from polybutadiene rubber, styrene-butadiene rubber, polyisoprene rubber, copolymers thereof or combinations thereof. 
     
     
         11 . The cured rubber composition of  claim 1 , wherein the sulfur vulcanization system include between 1 phr and 6 phr of sulfur. 
     
     
         12 . The cured rubber composition of  claim 1 , wherein the sulfur vulcanization system includes between 0.5 phr and. 4 phr of sulfur. 
     
     
         13 . The cured rubber composition of  claim 1 , wherein the 10% modulus of elongation at 23° C. is maintained to within 10% of the modulus of the cured rubber composition. 
     
     
         14 . The cured rubber composition of  claim 13 , wherein the 100% modulus of elongation at 23° C. is maintained to within 10% of the modulus of the cured rubber composition. 
     
     
         15 . The cured rubber composition of  claim 1 , wherein the 100% modulus of elongation at 23° C. is maintained to within 10% of the modulus of the cured rubber composition. 
     
     
         16 . A tire having a component made of the cured rubber composition of  claim 1 .